ITST Seminar – Widefield magnetic imaging with sensor spin ensembles

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Imaging weak magnetic fields is a powerful means to study structure, interactions, and ordering in many biological and condensed matter systems. Nitrogen-vacancy (NV) centers in diamond have recently emerged as highly sensitive magnetometers that operate over a wide range of temperatures and environmental conditions. Here I present an NV-based widefield magnetic microscope that, in a single architecture, can be continuously tuned to operate between a high magnetic sensitivity mode to a high spatial resolution mode. This flexible architecture allows for probing a wide dynamic range of magnetic length scales. I will also discuss our materials-based approach to maximizing the sensitivity of our magnetometer. By combining PECVD grown, nitrogen δ-doped diamond and electron irradiation with a transmission electron microscope [1], we have produced NV ensembles with coherence times exceeding 1 ms and magnetic sensitivities of 3 nT/√Hz. A suspected major limitation to increased magnetic sensitivity is the presence of paramagnetic P1 centers, substitutional nitrogen atoms in the diamond. I discuss the effect of P1 centers on NV coherence time and our experiments to quantify these effects. In parallel, we are working towards integrating our diamond magnetometer with biological systems. I will discuss recent progress towards using our magnetometer for sensing neuron action potentials and magnetite in cells.